As a sidenote, you should also ask here:
https://github.com/Bumblebee-Project/Bumblebee/issues/764
so that someone actually takes a look at the dumps you uploaded to lauchpad.
By a glance at it with my very limited knowledge it looks as if you are hit by this:
https://bugzilla.kernel.org/show_bug.cgi?id=156341
But then again, you should be able to work around this using acpi_osi=“!Windows 2015” as it disables the problematic function. Which didn’t work for you.